There are loads of different ways to fuse metals together. In this post, I’m going to introduce you to several of the more common methods that are popular. Here’s the additional information that we’ll cover for each type:
- How the process works
- What it’s used for
- Alternate names for the welding process
If there’s a particular type of welding that you’re interested in, use the table of contents to skim through the information.
According to most, this is the most basic kind of welding. It’s economical, easy to do, and it’s not expensive to get set up. It’s common to find this type on farms, construction sites, and in personal garages.
How Stick Welding Works
The electrodes are rods of metal that are selected to match the material being welded. They’re coated in a flux, which when incinerated release shielding gases that protect the melt pool from contaminants and oxidizers like oxygen. The electrodes are called rods.
A machine will pump electricity through the rod, which melts the metal and rod simultaneously. A clamp will ground the workpiece so that the circuit is closed and electricity can circulate.
Fun Fact: Stick welding didn’t get its name from the rods, which look like sticks. It’s because when you’re learning to arc weld, the teachers would tell the students to “stick the weld”, referring to the tapping motion that’s needed to knock off slag and start the arc.
For a diagram of how this all works, click here.
What Stick Welding is Used For
Generally, stick welding is used for welding steel plates. Since all you need is electricity and a supply of rods, it’s considered very mobile. It’s common to see structural applications for this type of welding, where the welding might be high up on a steel frame, welding plates and beams together. It’s also really common to see in the repair industry, especially with heavy equipment.
It’s also practical for exterior structural welding because it’s resistant to windy conditions. This is because the solid shielding flux is literally right at the arc, making it a great option for anyone welding outside.
It’s a great, general-purpose kind of steel welding. It’s super simple, easy to learn and easy to get into. That’s why this is arguably the most common type of welding around the world.
Technically, you can also use it for welding iron, stainless steels, aluminum, nickel, and copper alloys, but this is less common. It’s most commonly used for steel.
One of the downsides of stick welding is that it’s very smokey and dirty. You need to do it in a well ventilated area since the fumes are toxic. There’s a lot of slag that needs to be cleaned off the welding area. These are some of the main reasons that a lot of guys don’t really like it much.
Alternate Names for Stick Welding
Stick welding is also popularly known as arc welding. Those are the casual names. The technical name for it is Shielded Metal Arc Welding (SMAW) but it’s also known as Manual Metal Arc Welding (MMA or MMAW), or flux shielded arc welding.
This is another extremely common kind of welding. It’s relatively easy to learn, and it’s very versatile. If can be done manually, or it could be mounted up to a machine or robot for fully automatic welding. Robotic MIG welding is insanely fast and consistent.
How MIG Welding Works
A wire is fed through the handheld welding gun, and shielding gas is released around this wire. Pull the trigger and the wire feeds out and the gas is released. It’s basically a point and shoot system.
That’s not to say that you can do it properly without any kind of training (whether from school or YouTube). Learning how to properly set things like the wire feed rate, amperage, and gas flow rate take some time and practice. Even more practice is required to learn the steady motion required to get a nice, consistent weld.
If you want a diagram of the process, click here.
What MIG Welding is Used For
Since it’s such a continuous type of welding (you can keep going until your wire spool runs out or your tank of gas is empty) it’s a really popular option for manufacturing.
Cleanup is considerably less than with arc welding. There isn’t that heavy slag coating that needs to be chipped off. Usually, a quick once-over with a wire wheel or brush is all that’s needed.
Alternate Names for MIG Welding
MIG stands for Metal Inert Gas, and it’s actually a subset of Gas Metal Arc Welding (GMAW). Another type of welding within GMAW, and strongly related to MIG welding, is Metal Active Gas (MAG) welding.
The main difference between these two is the type of gases used. MIG uses only inert gas, usually argon or helium, to shield the arc from oxidizers. MAG welding has cocktails of different kinds of gases to better control things like the arc stability, the penetration of the weld pool (the depth of the molten metal) and the amount of spatter.
Generally, MIG is a more generic and common type of welding, whereas MAG is a bit more specialized.
This is a very different type of welding that the other ones that we’ve gone over so far. Instead of using electricity, oxyfuel welding uses a flame produced by gases.
How Oxyfuel Welding Works
The most well-known type of oxyfuel welding is oxy-acetylene welding. This combines oxygen and acetylene to create a really hot flame. A filler rod can be used to add more material when needed. It’s basically a two-handed process.
The flame from the welding torch is focused on the metal and creates a molten weld pool.
One key advantage of an oxyfuel system is that the welding torch can be quickly swapped out for a cutting torch. This has a lever that will blast a high amount of oxygen into the flame, which can turn thick steel into slag.
You can also use a larger, less focused torch tip (called a rosebud) to simply heat up metal. This can be a way to manually heat treat carbon steel. You can also use this as a way to expand metal to assemble/disassemble tight-fitting components.
There’s a lot that you can do with this single system.
Like diagrams? Then you’ll really enjoy this one.
What Oxyfuel Welding is Used For
This is really effective for sheet metal, and the fact that it doesn’t need electricity means that it’s very mobile. Just don’t drop the tanks. Those can go boom.
One disadvantage of this system is that it’s slow. You won’t often find an oxyfuel system used for welding in a production setting (although the cutting torches are extremely common). The main area you’ll see these used is for automotive exhaust repair, on farms, and among hobbyists.
Alternate Names for Oxyfuel Welding
Oxyfuel is a broad term that basically just means that you’re using oxygen along with another gas as fuel to make a really, really hot flame. The most common is oxyacetylene, but there can be other, more specialized gases used for more specialized applications.
You’ll also hear it called oxy welding or gas welding.
This is one of my personal favorites. TIG welding is super clean, and it’s extremely versatile in terms of the materials that it’s suitable for. It also requires considerable skill to do properly.
How TIG Welding Works
A TIG welder has a non-consumable tungsten electrode that creates the melt pool. It’s non-consumable because it’s not dual-purpose as an electrode and filler material simultaneously, as most other types of welding are.
Basically, electricity is pumped through the tungsten electrode, which is shielded by an inert gas (generally argon or helium) to protect the weld area. This will only melt the material. If you need to add more material to build up the weld area, a filler rod is used. This gives a huge amount of flexibility and control over the process.
The reason that it’s so tricky is that you have the welding gun (where the tungsten electrode is) in one hand and the filler rod in the other. And, because that isn’t complicated enough, you control the flow of electricity with a foot pedal.
You get a phenomenal amount of control, but there’s also a lot going on at once. That’s one of the reasons that it’s trickier to learn.
One of my favorite things about TIG welding is that it’s extremely clean. It doesn’t give off the fumes and smog that most other kinds of welding produce, and it doesn’t really splatter (as long as you’re doing it right). TIG welding stations are usually pristine.
If you want to see a diagram of the components of a TIG welder in action, click here.
What TIG Welding is Used For
While you can absolutely use a TIG welder for steel, it’s especially practical for other metals like stainless steel, aluminum, and titanium. A well done TIG weld is extremely high-quality and strong.
It can be used to weld very thin sections of metal, but it’s a slow process compared to MIG or arc welding.
This is a really common type of welding for pipefitters working with stainless pipes, as well as in automotive and aerospace applications.
Alternate Names for TIG Welding
TIG stands for Tungsten Inert Gas, but it’s also frequently referred to as GTAW – Gas Tungsten Arc Welding.
Ok, those are the three most common types of welding in terms of what people will make a career of. Now let’s get into some more specialized welding processes.
Because it’s cool.
Flux-Cored Arc Welding
Flux-Cored Arc Welding often goes by the acronym FCAW. It’s not the easiest to say that as a word. It kind of sounds like an angry chicken swearing at you. Anyway…
This is so similar to MIG welding that a lot of people confuse the two. There are a few differences worth knowing, though.
In terms of how it works, FCAW doesn’t use a shielding gas like MIG does. This makes it pretty convenient, since you only need the machine and the wire, and don’t have to worry about refilling your argon tank.
Instead, the FCAW machine has flux that’s inside the wire. Think of it almost like an inverted arc welder (where the flux is on the outside).
Here’s a diagram of what this looks like.
In terms of results, the two are not equal. FCAW is more convenient for the hobbyist, but MIG produces a better weld. FCAW is more prone to weld porosity, and the welding can produce a really high amount of nasty smoke and fumes. The wire itself is also more expensive.
One way to reduce porosity is to use an external shielding gas in addition to the flux core. This is commonly referred to as dual shield welding.
Since it’s so portable, it’s often used as an alternative to arc welding on construction sites. Since the shielding gas is released from the wire itself, it’s very suitable for windy conditions.
Electroslag welding, often abbreviated to ESW, is used to join metal plates. It’s done vertically, and it produces very high-quality welds.
It takes a bit to set up, but once it’s done it’s fairly automatic. You get the settings right on the machine and then just turn it on.
To start, you clamp two plates end-to-end with a gap in between and attach the welding machine.
The sides and bottom of the gap between the plates are capped off. Then flux is poured into this “basin”. The machine feeds a wire into the flux, and once it hits the bottom cap, it starts the arc. As the machine feeds the wire in, it builds up a big pool of melted metal. The molten metal rises up in the capped off area until it reaches the top of the workpiece.
This is a great way of joining thick, structural steel. It produces a ton of heat, but it has some distinct advantages. For one, it completes the weld in a single pass, where many passes might be required if the plates were to be joined by a welding process like MIG welding. It also gets great adhesion and avoids many of the common weld problems like pitting or oxidation.
Basically, it’s specialized but effective.
Plasma Arc Welding
Plasma arc welding sometimes goes by the abbreviation PAW.
This is extremely similar to TIG welding (GTAW).
The difference is that the electrode is within the body of the torch. That means that the shielding gas is away from the electrode and plasma can be created. Plasma is basically just energized gas.
The plasma is then forced out of a really small hole in a piece of copper. This makes the plasma travel crazy fast. Like speed of sound fast. It also can get up to 50,000 F or hotter.
What does all this mean?
It’s TIG welding on steroids. But more than that, this type of torch can also cut and spray coat hard materials.
Generally, this is used for metal up to one inch thick.
Submerged Arc Welding
This is actually pretty common. Sometimes referred to by the acronym SAW, it’s an extremely common way to weld pipes together end to end.
A coarse flux powder is laid down over the area to be welded via a tube. Inside the tube, there’s also a spool-fed wire that’s used as both an electrode and a filler material. This is generally a machine-controlled, automated process. The operator sets up the machine, adjusts the settings, then pushes the green button.
It’s kind of like the love child of arc and MIG welding. Instead of gas, you use a powder form of arc welding flux.
Laser Beam Welding (LBW) is a great way to get extremely narrow welds. Since the laser is so focused and high-powered, the welds also can be very deep and fast.
An major advantage of this type of welding is that it has a very small heat affected zone. Pretty well any kind of metal can be welded, although there can be issues with high carbon steels cracking due to the high heat.
This kind of welding is popular in the automotive industry, and it’s easy to automate with robotics and machinery.
For semi-automatic setups, you can manually add filler rod. You can also use powdered metal as a filler.
If you want to see a video of how this works, click here (YouTube).
Electron Beam Welding
This is extremely similar in function to laser welding. They both are considered “power beam” welding.
So what are the differences? Here’s electron beam welding VS laser beam welding:
|Electron Beam||Laser Beam|
|Machine is cheaper||Machine is more expensive|
|Running cost is cheaper||Running cost is more expensive|
|Power efficiency is about 90%||Power efficiency is about 10%|
|Does not need filler/shielding gas||Needs gas like nitrogen or argon to protect weld pool|
|Can weld dissimilar metals||Can’t. It just can’t.|
|Higher quality weld, very stable||Lower quality weld, tends to have porosity issues|
|Component size is limited since welding is done in a vacuum chamber||Component size is generally not limited; there is no chamber as shielding gas is used to protect weld area|
|Really fast||Reasonably fast|
|Can penetrate really deep; up to a 40:1 ratio||Can penetrate reasonably deep; up to 10:1 ratio|
So overall, EBW is generally better for small or medium sized components (although that depends on the size of the machine) and for high volume.
LBW is better for very large components, or low volume, since it can be done semi-automatically.
This is insanely easy, and it’s used for sheet metal. Basically two electrodes pinch two pieces of sheet metal together. They blast electricity into the metal, partially melting it and fusing the two pieces together.
It’s an extremely fast process, and it can be done either manually or be rigged up to a robot for total automation. It’s an extremely common process for the automotive industry. If you’ve ever done work on a car, you’ll have seen little round indents on the unibody where the pieces have been spot welded together.
This is basically the most ancient way of welding metal together. Heat up two pieces of similar metal until they’re bright orange, and whack them together with a hammer.
This is a skill that lots of blacksmiths use. Generally, they’ll grind the two pieces clean and fit them up. Then they’ll sprinkle some flux in between the glowing metal so that oxygen doesn’t mess up the surfaces. Then they pound it with a hammer or squash it in a press.
Generally, it’s not the most stable process. A lot can go wrong. But it is fun.
Other Kinds of Welding
Seriously, there are too many types of welding to name. Here are a few extras just for kicks:
Resistance seam welding can make long, continuous welds. It uses copper electrodes to make constant contact with the pieces being welded together. The electrodes are shaped like wheels so they can roll across the material continuously. They apply both heat (electricity) and pressure, so the resulting welds are extremely strong. This is a common way of making things like ducts.
Friction stir welding is an interesting process where a carbide cylinder is rotated at a high RPM, pressed into two pieces of metal, then fed along a seam. The metal melts from the high friction, and it’s stirred together while in that molten state. It’s commonly used for creating very strong welds in aluminum.
Thermite welding is used mainly by railroads to join rails together. It’s proper name is exothermic welding. It uses something known as thermite (metal powder that ignites and burns at extreme temperatures). It can join a lot of different kinds of metals, as well as dissimilar metals. Generally, a mold is put around the pieces to be joined, the ends are pre-heated, then the thermite is lit up. This makes molten metal that can be essentially cast in place.
Ultrasonic welding is generally used for thin sheet metal or wires. Vibrating them at high frequency and under high pressure fuses them together. This is also common for plastics.
If you’re interested in getting more involved in welding as a career, make sure you check out my guide on how to become a welder.